In January alone, 80 children were killed, the United Nations High Commissioner for Human Rights said.

Pillay cited unspecified reports as the source of her statement, which came just three weeks after the United Nations Children's Fund made the previous estimate.

Pillay, said the international community has to take action to prevent Syrian security forces from continuing their attacks against civilians, which she said had resulted in "countless atrocities."

"There must be an immediate humanitarian cease-fire to end the fighting and bombardments," Pillay told an urgent meeting of the U.N. Human Rights Council.

She urged Syria to end all fighting, allow international monitors to enter the country and give unhindered access for aid agencies to enter Homs and other embattled cities.

The appeal prompted a bitter riposte from Syria's ambassador to the United Nations in Geneva, who accused the 47-nation council of promoting terrorism in his country.

Pillay cited the report of a U.N. expert panel last week, which concluded that Syrian government officials were responsible for "crimes against humanity" committed by security forces against opposition members. The crimes included shelling civilians, executing deserters and torturing detainees. Some opposition groups, too, had committed gross abuses, it said.

The panel has compiled a confidential list of top-level Syrian officials who could face prosecution over the atrocities.

Pillay reiterated her call for Syria to be referred to the International Criminal Court "in the face of the unspeakable violations that take place every moment." "More than at any other time, those committing atrocities in Syria have to understand that the international community will not stand by and watch this carnage and that their decisions and the actions they take today ultimately will not go unpunished," she said.

Two activist groups say a British journalist who was wounded in Syria last week has been smuggled to neighboring Lebanon.

The Syrian opposition group Local Coordination Committees and global group Avaaz said Tuesday that Paul Conroy was the only foreign journalist to escape to Lebanon. Rima Fleihan, an LCC spokeswoman, said Conroy was smuggled by Syrian army defectors.

In Beirut, a British embassy official told The Associated Press that London is working on repatriating Conroy, who was injured in the restive central city of Homs along with French journalist Edith Bouvier. The LCC spokeswoman said Bouvier is still in Homs.

American Marie Colvin and Frenchman Remi Ochlik were killed in the same attack and their bodies are still in Syria.

Members of the council are expected to pass a resolution Tuesday condemning "widespread and systematic violations of human rights and fundamental freedoms by the Syrian authorities."

A draft resolution supported by many Arab and Western nations says the regime's use of heavy artillery and tanks to attack civilian areas has contributed to the deaths of thousands of people since March.

Syria called for countries to stop "inciting sectarianism and providing arms" to opposition forces in the country, and charged that sanctions imposed by some countries were preventing Damascus from buying medicines and fuel.

Faysal Khabbaz Hamoui, Syria's ambassador to the United Nations in Geneva, stormed out of the U.N. Human Rights Council after delivering an angry speech to the Geneva forum's emergency debate on the deteriorating situation in Syria called at the request of Gulf countries and Turkey, and backed by the West.

"We reaffirm to all those alleged friends of the Syrian people that the simple step to immediately help the Syrian people is to stop inciting sectarianism, providing arms and weapons and funding and putting the Syrian people one against the other," Khabbaz Hamoui said.

"Unjust and unilateral sanctions imposed by some countries on the Syrian people are preventing access to medicines, to fuel in all forms as well as electricity, and are also impeding bank transfers to buy these materials," he said

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